The present invention relates to new hydrolysates and/or condensates of epoxy- and silane-functional oligomers and polymers. The present invention also relates to a new process for preparing hydrolysates and/or condensates of epoxy- and silane-functional oligomers and polymers. The present invention further relates to the use of the new hydrolysates and/or condensates of epoxy- and silane-functional oligomers and polymers and of the hydrolysates and/or condensates of epoxy- and silane-functional oligomers and polymers prepared by the new process as new curable compositions or for preparing new curable compositions. The present invention relates not least to the use of the curable compositions for producing new cured compositions, especially coatings and paint systems, and also moldings, especially optical moldings, and self-supporting sheets.
Curable compositions based on hydrolysates and/or condensates of epoxy-functional silanes are known from, for example, patent applications EP 1 179 575 A 2, WO 00/35599 A, WO 99/52964 A, WO 99/54412 A, DE 197 26 829 A 1 or DE 195 40 623 A 1. They serve in particular to produce highly scratch-resistant coatings.
Curable compositions based on silanes which contain at least one olefinically unsaturated group, in particular a vinyl group or a methacrylate or acrylate group, such as vinyltrimethoxysilane or methacryloyloxypropyltrimethoxysilane (MPTS), for example, are known from patent applications WO 00/22052 A, WO 99/54412 A, DE 199 10 876 A 1 or DE 197 19 948 A 1
According to international patent application WO 99/54412 A, for example, MPTS is hydrolyzed and/or condensed in the presence of gamma-AlO(OH) nanoparticles. The resulting gel is evaporated down and used as a powder clearcoat material. The applied powder clearcoat material is cured thermally.
According to patent applications WO 00/22052 A, DE 199 10 876 A 1 or DE 197 19 948 A 1, for example SiO2 nanoparticles are silanized with MPTS and mixed with polyfunctional acrylates, such as trimethylolpropane triacrylate The resulting suspensions can be polymerized with UV radiation or electron beams.
Thermally curable compositions based on copolymers containing epoxide groups and hydrolyzable silane groups are known from American patent U.S. Pat. No. 4,772,672 A. The curable compositions must be cured using aluminum or zirconium chelate complexes. The curable compositions can have from 0.1 to 1% by weight of water added to them, based on their respective total amount, in order to accelerate the cure.
An essential objective of these developments is to provide curable compositions for producing cured compositions, especially coatings and paint systems, and also moldings, especially optical moldings, and self-supporting sheets.
The curable compositions ought to be easy to prepare with great reproducibility and for use in the liquid state ought to have a solids content >30% by weight without detriment thereby to their transportability, storage stability or processing properties, in particular their application properties
The curable compositions ought to give cured compositions, especially coatings and paint systems, more particularly clearcoats, moldings, especially optical moldings, and self-supporting sheets which are highly scratch-resistant and chemicals-stable. In particular it ought to be possible to produce the coatings and paint systems, more particularly the clearcoats, in film thicknesses>40 μm without the appearance of stress cracks. This is an essential prerequisite for the use of the coatings and paint systems, especially the clearcoats, in the technologically and esthetically particularly demanding segment of automotive OEM finishing. In this context they are required in particular to exhibit a particularly high carwash resistance, manifested in the AMTEC carwash test, which is relevant to practice, by a residual gloss (20° to DIN 67530>70% of the original gloss.
The existing curable and cured compositions are unable, however, to meet this profile of requirements to its full extent.
It is an object of the present invention to provide new materials containing epoxide groups and silane groups which allow the production of new curable and cured compositions which do meet the profile of requirements depicted above to its full extent. The new epoxy-functional and silane-functional materials ought, furthermore, to be easy to prepare with very great reproducibility, ought not to pose any environmental problems, and ought consequently not to require any approval under chemicals law.